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SM 25x275 [2xM8] / N42 - magnetic separator

magnetic separator

Catalog no 130294

GTIN/EAN: 5906301812876

5.00
Diameter Ø
25 mm [±1 mm]
Height
275 mm [±1 mm]
Weight
1060 g
Magnetic Flux
~ 6 500 Gauss [±5%]
check technical specifications »

620.00 zł net / pcs

762.60 zł with VAT (23% VAT) / pcs

price for transport

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Frequently asked questions

Which rod should I choose for fine contamination?
For particles below 0.5 mm — a Ø32 mm rod in grade N52, with surface induction of about 10,000 Gs. A Ø25 rod in grade N42 gives about 6,500 Gs and is chosen for contamination above 1 mm: bolts, washers, pieces of wire.
Which rod pitch should I choose?
The narrow pitch, 40 mm centre to centre, for fine free-flowing fractions — it gives denser coverage of the cross-section. The wide pitch, 50 mm, for granulates and for damp, greasy or sticky materials, where a narrow pitch risks the material bridging above the rods.
Why does efficiency drop after a few weeks of operation?
Almost always because the separator has not been cleaned. The layer of captured particles shields the field, and further particles settle on that layer rather than on the rod surface, where the gradient is far stronger. The magnets themselves do not weaken at that rate.

Guides from the knowledge base

Want to talk magnets?

Call us now +48 888 99 98 98 alternatively let us know using contact form the contact section.
Specifications and structure of a neodymium magnet can be estimated using our power calculator.

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Technical data of the product - SM 25x275 [2xM8] / N42 - magnetic separator

Specification / characteristics - SM 25x275 [2xM8] / N42 - magnetic separator

properties
properties values
Cat. no. 130294
GTIN/EAN 5906301812876
Production/Distribution Dhit sp. z o.o.
ul. Zielona 14 05-850 Ożarów Mazowiecki PL
Country of origin Poland / China / Germany
Customs code 85059029
Diameter Ø 25 mm [±1 mm]
Height 275 mm [±1 mm]
Weight 1060 g
Material Type Stainless steel AISI 304 / A2
Magnetic Flux ~ 6 500 Gauss [±5%]
Size/Mount Quantity 2xM8
Polarity circumferential - 10 poles
Casing Tube Thickness 1 mm
Manufacturing Tolerance ±1 mm

Magnetic properties of material N42

Specification / characteristics SM 25x275 [2xM8] / N42 - magnetic separator
properties values units
remenance Br [min. - max.] ? 12.9-13.2 kGs
remenance Br [min. - max.] ? 1290-1320 mT
coercivity bHc ? 10.8-12.0 kOe
coercivity bHc ? 860-955 kA/m
actual internal force iHc ≥ 12 kOe
actual internal force iHc ≥ 955 kA/m
energy density [min. - max.] ? 40-42 BH max MGOe
energy density [min. - max.] ? 318-334 BH max KJ/m
max. temperature ? ≤ 80 °C

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C
properties values units
Vickers hardness ≥550 Hv
Density ≥7.4 g/cm3
Curie Temperature TC 310 °C
Curie Temperature TF 590 °F
Specific resistance 150 μΩ⋅cm
Bending strength 250 MPa
Compressive strength 1000~1100 MPa
Thermal expansion parallel (∥) to orientation (M) (3-4) x 10-6 °C-1
Thermal expansion perpendicular (⊥) to orientation (M) -(1-3) x 10-6 °C-1
Young's modulus 1.7 x 104 kg/mm²

Table 1: Rod construction
SM 25x275 [2xM8] / N42

Parameter Value Description / Unit
Diameter (Ø) 25 mm
Total length 275 mm (L)
Active length 239 mm
Section count 10 modules
Dead zone 36 mm (2x 18mm starter)
Weight (est.) ~1026 g
Active area 188 cm² (Area)
Housing material AISI 304 1.4301 (Inox)
Surface finish Ra < 0.8 µm Polished
Temp. class 80°C Standard (N)
Force loss (at max °C) -12.8% Reversible loss (physics)
Force (calculated) 10.6 kg (theor.)
Induction (surface) ~6 500 Gauss (Max)
Max T = 80°C. Construction data for M8/M10 thread series.

Chart 2: Field profile (10 sections)

Simulation: 10 magnetic modules (pitch 23 mm).

Chart 3: Temperature performance

Technical and environmental data

Material specification

iron (Fe) 64% – 68%
neodymium (Nd) 29% – 32%
boron (B) 1.1% – 1.2%
dysprosium (Dy) 0.5% – 2.0%
coating (Ni-Cu-Ni) < 0.05%

Ecology and recycling (GPSR)

recyclability (EoL) 100%
recycled raw materials ~10% (pre-cons)
carbon footprint low / zredukowany
waste code (EWC) 16 02 16
Safety card (GPSR)
responsible entity
Dhit sp. z o.o.
ul. Kościuszki 6A, 05-850 Ożarów Mazowiecki
tel: +48 22 499 98 98 | e-mail: bok@dhit.pl
batch number/type
id: 130294-2026
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It is the "heart" of every magnetic filter used in industry for cleaning raw materials. Its task is separation (separation) of metal filings from the transported material. High magnetic induction on the surface allows catching the finest iron particles.
The outer layer is hygienic acid-resistant steel, approved for food contact. The center is filled with NdFeB magnets and pole pieces, arranged to maximize the field on the tube surface. Such construction ensures full resistance to corrosion, water, oils, and acids.
Metal filings stick to the surface very strongly, so cleaning requires strength or cleverness. You can use compressed air or special non-magnetic strippers (rings). In industry, cover tubes (so-called Easy Clean system) are used, from which the magnetic insert slides out.
The more Gauss, the smaller and more weakly magnetic particles will be effectively caught. Standard rods (~8000 Gs) are sufficient for catching screws, nails, and steel shavings. For the food and precision industry, we recommend the highest induction parameters.
We fulfill individual orders for bars perfectly matched to your machine or separator. You can choose a mounting method consistent with your technical design. We ensure fast realization of special orders and technical advice.

Pros and cons of Nd2Fe14B magnets.

Benefits

Apart from their superior holding force, neodymium magnets have these key benefits:
  • They have stable power, and over nearly ten years their performance decreases symbolically – ~1% (according to theory),
  • They are noted for resistance to demagnetization induced by presence of other magnetic fields,
  • Thanks to the glossy finish, the plating of Ni-Cu-Ni, gold-plated, or silver gives an elegant appearance,
  • Magnetic induction on the working layer of the magnet remains strong,
  • Neodymium magnets are characterized by very high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
  • Thanks to freedom in designing and the ability to modify to complex applications,
  • Wide application in high-tech industry – they are used in data components, brushless drives, medical equipment, also technologically advanced constructions.
  • Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Weaknesses

Disadvantages of NdFeB magnets:
  • At very strong impacts they can crack, therefore we advise placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
  • Neodymium magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
  • Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
  • Due to limitations in realizing nuts and complicated forms in magnets, we recommend using casing - magnetic holder.
  • Possible danger to health – tiny shards of magnets are risky, in case of ingestion, which is particularly important in the context of child health protection. Furthermore, small components of these products are able to be problematic in diagnostics medical when they are in the body.
  • Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Pull force analysis

Maximum magnetic pulling force – what affects it?

The load parameter shown concerns the limit force, obtained under laboratory conditions, specifically:
  • with the application of a sheet made of low-carbon steel, ensuring full magnetic saturation
  • with a thickness minimum 10 mm
  • with an polished touching surface
  • under conditions of ideal adhesion (metal-to-metal)
  • under vertical force direction (90-degree angle)
  • at ambient temperature room level

Determinants of lifting force in real conditions

Real force impacted by specific conditions, mainly (from priority):
  • Clearance – existence of any layer (rust, dirt, gap) acts as an insulator, which lowers power rapidly (even by 50% at 0.5 mm).
  • Load vector – highest force is reached only during pulling at a 90° angle. The force required to slide of the magnet along the surface is typically many times lower (approx. 1/5 of the lifting capacity).
  • Steel thickness – too thin steel does not accept the full field, causing part of the flux to be wasted into the air.
  • Steel grade – the best choice is high-permeability steel. Hardened steels may attract less.
  • Surface finish – ideal contact is possible only on smooth steel. Rough texture reduce the real contact area, reducing force.
  • Temperature – temperature increase results in weakening of force. It is worth remembering the maximum operating temperature for a given model.

Lifting capacity was assessed with the use of a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, however under parallel forces the load capacity is reduced by as much as 75%. Additionally, even a small distance between the magnet and the plate decreases the lifting capacity.

Precautions when working with neodymium magnets
Physical harm

Big blocks can break fingers in a fraction of a second. Do not put your hand between two attracting surfaces.

ICD Warning

Medical warning: Neodymium magnets can turn off pacemakers and defibrillators. Stay away if you have medical devices.

Threat to electronics

Powerful magnetic fields can erase data on credit cards, HDDs, and storage devices. Maintain a gap of min. 10 cm.

Safe operation

Before use, check safety instructions. Uncontrolled attraction can break the magnet or injure your hand. Think ahead.

Material brittleness

Beware of splinters. Magnets can explode upon violent connection, ejecting shards into the air. We recommend safety glasses.

Thermal limits

Regular neodymium magnets (grade N) lose power when the temperature exceeds 80°C. The loss of strength is permanent.

Choking Hazard

NdFeB magnets are not suitable for play. Accidental ingestion of multiple magnets may result in them attracting across intestines, which poses a severe health hazard and requires urgent medical intervention.

Nickel coating and allergies

Certain individuals have a hypersensitivity to nickel, which is the standard coating for neodymium magnets. Prolonged contact might lead to dermatitis. It is best to wear safety gloves.

Fire risk

Machining of neodymium magnets poses a fire hazard. Neodymium dust reacts violently with oxygen and is hard to extinguish.

Impact on smartphones

GPS units and mobile phones are highly sensitive to magnetism. Close proximity with a powerful NdFeB magnet can permanently damage the sensors in your phone.

Caution! Want to know more? Read our article: Are neodymium magnets dangerous?